Fix page zoom to be frame-centric for out-of-process frames.

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index d37c506630a9dfdfef1d643462d78d2143eec193..23d28d91d2b8da19e253b541b7115fe2c555ca33 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -395,10 +395,12 @@ void FrameView::setFrameRect(const IntRect& newRect)
     const bool frameSizeChanged = oldRect.size() != newRect.size();
 
     m_needsScrollbarsUpdate = frameSizeChanged;
-    // If layout is clean then update scrollbars immediately otherwise wait
-    // for layout to ensure content size is correct too.
-    if (!needsLayout())
-        updateScrollbarsIfNeeded();
+    // TODO(wjmaclean): find out why scrollbars fail to resize for complex
+    // subframes after changing the zoom level. For now always calling
+    // updateScrollbarsIfNeeded() here fixes the issue, but it would be good to
+    // discover the deeper cause of this.
+    // http://crbug.com/000000 <-- Don't land without filing this bug
+    updateScrollbarsIfNeeded();
 
     frameRectsChanged();